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Identification Guide

American art pottery marks.
How to identify the maker.

A practical guide to the most common American art pottery marks — from the Rookwood flame to the Grueby lotus — and the artist initials that dramatically affect value.

Reading the Bottom

How to identify American art pottery by its marks

American art pottery studios left a remarkably complete paper trail on the bottoms of their pieces. Factory stamps, artist initials, shape numbers, and date codes make most pieces identifiable with confidence — if you know what to look for. This guide covers the major American art pottery marks and what each one tells you about the piece.

Rookwood — the flame mark

Rookwood, founded in Cincinnati in 1880, uses the most famous mark in American art pottery: a reversed RP monogram surrounded by flames. The RP cipher was introduced in 1886. One flame was added in 1887, and one additional flame each year through 1900, when the mark reached fourteen flames. From 1901 onward, Roman numerals below the cipher indicate the year (I = 1901, II = 1902, XX = 1920). Every Rookwood piece after 1886 can be dated precisely from the mark. Artist initials appear incised or painted near the mark on artist-decorated pieces.

Grueby — the lotus stamp

Grueby Faience, made in Boston from 1894 until the early 1910s, used a circular impressed stamp showing a lotus blossom at the center with "Grueby" or "Grueby Faience" wrapping the edge. The stamp is usually small, cleanly impressed, and centered on the underside. Grueby pieces are known for their matte green glaze and organic modeled decoration — often leaves and buds — carved into the form. Authentic Grueby is consistently collected at the top of the American art pottery market.

Newcomb College — the NC cipher

Newcomb College Pottery, produced at Sophie Newcomb College in New Orleans from 1895 to 1940, carries an "NC" monogram — often inside a circle — on the bottom. Most Newcomb pieces also include the decorator's initials, a potter's initials, a shape number, and a date letter code. Few American art potteries are as thoroughly documented. Newcomb decoration features soft blues, greens, and pinks with Louisiana landscape motifs: magnolia, live oak with Spanish moss, cypress, and other regional plants.

Marblehead — the ship with an M

Marblehead Pottery of Marblehead, Massachusetts (1904–1936) used an impressed mark showing a small sailing ship flanked by an "M" on each side. The ship stamp is tidy and distinctive. Marblehead pieces typically have simple forms and muted matte glazes — blue, green, and yellow — sometimes with conventionalized decoration. Collectors look for larger vases and pieces with decoration, as simple unmarked production forms are more common.

Teco — the stacked T

Teco pottery, the art line of the Gates Pottery in Terra Cotta, Illinois (1902–1923), used an incised "Teco" mark with the T and O often stacked or arranged in a distinctive geometric pattern. Teco pieces are known for architectural forms and matte glazes, especially a signature green. Larger architectural-style vases in good condition are strongly collected.

Van Briggle — the double-A monogram

Van Briggle, founded in Colorado Springs in 1899, uses a double-A cipher — two A's joined together — impressed or incised on the bottom. Early Van Briggle (1901–1912) included a date in Roman or Arabic numerals alongside the cipher. Dated early pieces are dramatically more valuable than later production. The AA mark continued to be used on mass-produced Van Briggle for decades after Artus Van Briggle's death, and later undated pieces bring only a small fraction of the prices for early dated work.

Weller — varied scripts over decades

Weller Pottery of Zanesville, Ohio (1872–1948) used many marks over its long history: impressed "Weller" scripts of various styles, "Weller Pottery" in block letters, and different marks for different decorative lines. Earlier Weller marks are usually impressed or incised. Later production often used printed or stamped marks. The specific mark can help date a piece and identify its decorative line (Louwelsa, Etna, Sicard, Hudson, and many others).

Fulper and Pewabic

Fulper Pottery of Flemington, New Jersey, used a vertical rectangular ink stamp reading "Fulper" along with impressed racetrack or oval marks at various points in its history. Fulper specialized in experimental crystalline and matte glazes, some of which are highly collected. Pewabic Pottery of Detroit used an impressed or incised "Pewabic" mark with a maple leaf design, and is known for iridescent glazes and architectural tiles. Both are important American studios whose marked pieces reward identification.

Artist initials and why they matter

On makers like Rookwood, Newcomb College, and Grueby, individual decorators signed their work with incised or painted initials near the factory mark. Artist identification transforms a piece from anonymous factory production into the signed work of a named craftsperson, and certain decorators command dramatic premiums. Kataro Shirayamadani at Rookwood, Sadie Irvine at Newcomb, and the small cadre of Grueby decorators are examples of signatures that can multiply a piece's value. Always photograph every incised or painted letter on the bottom — even a single initial can change everything.

Quick Reference

  • Rookwood: RP flame mark + year (Roman numerals)
  • Grueby: Circular lotus stamp
  • Newcomb College: NC cipher + artist + date
  • Marblehead: Ship flanked by M's
  • Teco: Incised "Teco" stacked
  • Van Briggle: Double-A monogram (early = dated)
  • Weller: Various Weller scripts
  • Fulper: Vertical rectangular stamp
  • Pewabic: Impressed name with maple leaf

Photo Tip

Photograph the entire bottom of the piece in good, raking light. Capture the main factory mark, any shape numbers, date codes, and — most importantly — any incised or painted artist initials. A magnifying glass helps with faint or shallow marks. Even a single clear photo of the bottom usually identifies the maker.

An Honest Take

What usually isn't valuable

Not every marked piece is a major find. These are the common patterns that disappoint.

Later Van Briggle without a date

The double-A cipher continued in use for decades after the early period ended. Undated Van Briggle produced from the 1920s onward is legitimate but brings a small fraction of what dated early work sells for. Most Van Briggle found in estates is later production with the AA mark but no accompanying date, and it typically sells in the $25–$150 range regardless of form or size.

Reproduction Rookwood

Rookwood has been reproduced and imitated. Some reproductions carry marks designed to look like the flame cipher. Authentic Rookwood has specific characteristics in the clay body, glaze, and mark placement that a specialist can identify. A "Rookwood" mark on a piece without the other hallmarks of authentic factory production is worth a careful look before assuming it is genuine.

Unmarked pieces in art pottery style

Many mid-century production potteries made work that looked like art pottery without being made by any of the important studios. Unmarked pieces with matte green glazes or other art-pottery-like finishes are usually production ware from small or anonymous factories. In the absence of a mark, attribution is difficult and value is modest.

Late-period production from major names

Rookwood, Roseville, Weller, and most major American potteries continued production for decades, sometimes with reduced standards. Later mass-market pieces from these factories — including post-1930 production Rookwood without artist decoration — carry authentic marks but sell for a small fraction of what earlier artist-involved work commands. The mark alone is not enough; the era, glaze line, and presence or absence of artist initials are what matter.

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Common Questions

Frequently asked about American art pottery marks

Almost always on the bottom of the piece. Factory stamps, incised signatures, and painted logos appear on the underside, typically within the foot ring or at the center of the base. Shape numbers and date codes may appear nearby. Artist initials, when present, are usually incised or painted close to the factory mark. A few makers also applied paper labels, though most have been lost over time. Always turn the piece over and photograph the entire base in good light.
The Rookwood flame mark is an RP monogram — a reversed R and P — surrounded by flames. It was introduced in 1886, with the first flame added in 1887. One additional flame was added each year until 1900, when the mark reached fourteen flames. After 1900, Roman numerals below the mark indicate the year (I = 1901, II = 1902, and so on). This dating system lets collectors and specialists date any Rookwood piece precisely.
Grueby pottery — produced in Boston from 1894 to around 1911 — used a circular impressed stamp featuring a lotus blossom in the center with the word "Grueby" or "Grueby Faience" around the edge. The stamp is usually small, circular, and clearly impressed into the clay on the bottom of the piece. Grueby pieces often also carry artist initials nearby. Grueby is one of the most collected names in American art pottery, and a legitimate Grueby mark significantly affects value.
Newcomb College pottery carries an "NC" monogram, often inside a circle. Produced at Sophie Newcomb College in New Orleans from 1895 to 1940, Newcomb pieces typically show soft blue, green, and pink glazes with hand-painted or incised Louisiana landscape motifs (magnolia, live oak, cypress). In addition to the NC cipher, Newcomb pieces often carry the decorator's initials, a potter's mark, a shape number, and a date letter code — making them some of the most thoroughly documented pieces in American art pottery.
Artist initials identify individual decorators and often dramatically increase value. Factory marks tell you the maker; artist initials tell you who painted or decorated the piece. For makers like Rookwood, Newcomb College, and Grueby, certain artists are far more sought after than others, and their signed work can sell for several times what anonymous factory production brings. Incised or painted initials near the factory mark are among the most important features to photograph when evaluating inherited art pottery.
Van Briggle pottery uses a double-A monogram — two A's joined to form a symbol resembling intertwined letters — impressed or incised on the bottom. Early Van Briggle (1901–1912) also included the date in Roman numerals or Arabic numerals, which substantially affects value. Early-dated pieces are worth far more than later production, which can continue bearing the same AA cipher without a date. A Van Briggle mark alone is not enough to establish value — the presence or absence of a date is decisive.